This invention relates to the field of firearms and provisions for modifying semi-automatic firearms for training purposes. In particular, it relates to reliable ejection of ammunition from firearms that have been modified to straight blow-back action so that they can fire low-energy ammunition.
In military and police firearms applications almost all of the ammunition consumed is used for training. For some training purposes, however, normal ammunition is not adequate. An alternative type of known training ammunition, represented by U.S. Pat. No. 5,359,937 (adopted herein by reference), fires a low-mass projectile relying on a special, low-energy cartridge designed expand telescopically to provide cycling of suitably modified, recoil-operated automatic and semi-automatic weapons. This is effected by providing the cartridge with a sabot that is slidingly fitted into the cartridge casing.
An advantage of the low-energy training ammunition is that it has a shorter range and lower penetration capacity than standard ammunition. This permits use of smaller, less secure firing ranges as training facilities. If standard ammunition were accidentally employed in these facilities, unexpected dangers would arise from the increased striking power and range of standard ammunition.
The weapon modifications required to permit cycling while firing low-energy ammunition generally include replacing or modifying the barrel and sometimes replacing or adding certain other components, depending on the weapon involved. The low-energy cartridge represented by U.S. Pat. No. 5,359,937, in combination with a substitute training barrel, allows normal recoil and cartridge case ejection through a blow-back action.
When firing standard ammunition, with its abundant associated energy, it is necessary in many weapons, particularly pistols, to lock the barrel to the slide during the beginning of their rearward motion for a period of time long enough for the projectile to exit the barrel muzzle while the breech is still closed. This allows the chamber pressure to drop before the breech opens to extract and eject the spent cartridge case. A locking mechanism couples the slide and barrel together for the first portion of the recoil, and then releases the slide, usually with the aid of a cam. Thus, in such standard weapons, the barrel recoils, at least partially, with the slide. Upon unlocking, the slide continues its rearward travel while the barrel stops in the proper position to receive the next round from the magazine to be chambered by the slide as it returns to its in-battery position.
Associated with the barrel locking and unlocking action of the slide in a standard weapon, there may also be an up-and-down pivotal movement of the chamber end of the barrel. This pivoting motion may be caused by a cam located under the barrel. When in battery, the barrel is in its most upward position such that the center of the primer of the chambered round is aligned with the firing pin. After firing, the chamber end of the barrel drops to its most downward position, which brings it in line with the ejector.
In a training barrel it is necessary to omit this barrel locking mechanism and, by so doing, the recoil action becomes pure blow-back of the slide only. This must be done because there is not enough energy in low-energy training cartridges to precipitate sufficient recoil to unlock the barrel and the slide in their standard configurations. A training barrel of the type addressed by this invention is similar in most aspects to the standard barrel for a particular pistol with a barrel locking mechanism, but is modified, in part, by removing the locking mechanism, so that the barrel and the slide are no longer fully held together for the first portion of the recoil cycle. Thus, upon firing, the slide is free to move rearwards from its in-battery position unencumbered by the barrel.
In some converted pistols, after the mechanism for momentarily locking the barrel to the slide has been removed so that the weapon can fire low-energy ammunition, as represented by U.S. Pat. No. 5,359,037, the training barrel is restrained from longitudinal motion during the firing cycle. This is achieved by modifying the cam configuration such that the barrel is permanently attached to the pistol receiver (frame). By so doing, maximum energy is transferred to the slide, thereby contributing to reliable weapon cycling.
In some 9 mm pistols, after the locking mechanism has been removed so that the weapon can fire low-energy ammunition, an ejection problem may arise if the training barrel does not drop down or descend far enough during the recoil cycle to bring the expended training case into line with the ejector for extraction. Should this occur, the spent case may not come into proper contact with the ejector, thereby causing jamming due to failure to eject.
It is, therefore, an objective of this invention to provide an alternative training barrel system for this class of firearms that will ensure reliable ejection of the spent training cases.
The invention is applicable to pistols wherein it is necessary to retain an up-and-down movement of the chamber end of the training barrel even if the barrel is not able to move longitudinally. This is required so that the primer will be in line with the firing pin (most upward position of the barrel) when the weapon is in battery, and the expended case will be in line with the ejector (most downward position of the barrel) during the latter part of the recoil cycle. It is, therefore, another objective of this invention to ensure reliable ejection of spent training cases from training barrels which retain an up-and-down motion in pistols converted to fire low-energy ammunition.
Further, the concept of converting a pistol so that it can fire low-energy ammunition for training purposes is basically to replace the service barrel by a training barrel without modifying the slide or the receiver. In this way, the weapon can be rapidly reconverted to fire live ammunition again by removing the training barrel and reinstalling the service barrel. Other minor modifications may be necessary (e.g., to the recoil spring rod) but they, too, can be quickly reverted to their original configurations. It is, therefore, a third objective of this invention to provide a training barrel system for this class of training firearm that will allow quick and easy assembly/disassembly of the training barrel without modification to either the receiver or the slide.
The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.
This invention is directed to an automatic pistol adapted to fire low-energy training ammunition by the substitution of a training barrel that omits the barrel-locking feature normally present, especially in combination with a barrel pivoting/cam system. Said substitution is effected without modification to either the receiver or the slide of the pistol being converted to fire training ammunition. The invention provides a system for orienting the spent cartridge case such that it will strike the ejector during the recoil cycle, thereby being knocked out of the weapon, while in no way affecting the alignment of the firing pin with the primer when the weapon is in battery (i.e., ready to fire).
According to the invention, a firearm preferably intended for use with a telescopically expanding cartridge, such as in U.S. Pat. No. 5,359,937 is provided with a training barrel and a standard service slide which has an ejection port with a forward vertical face. The training barrel and service slide are at no time locked together and the training barrel is restrained from longitudinal movement, but free to move up and down at its chamber end. The firearm into which this training barrel is to be installed has an ejector member located within the firearm frame rearwardly of the barrel at a position that is beneath the geometric extension of a cartridge chambered in the barrel when in the in-battery position.
The training barrel of the invention is similar to a standard barrel in that it includes a bore with a chamber; but differs from a standard barrel in that:
(1) the normal cam configuration below the chamber is removed to eliminate interaction with the frame, as described above; and
(2) a cam surface is added to the top of the barrel above the chamber to induce an up-and-down motion of the chamber end of the barrel as the slide moves over it.
This cam surface is contacted by the overlying slide on firing in order to effect the required downward displacement.
When in battery, the cam surface of the training barrel above the chamber is located in the ejection port of the slide where its forward end abuts the forward vertical face of the ejection port. When the slide recoils after firing under the impetus of the telescopically expanding cartridge, it passes over the cam surface of the training barrel, thereby forcing said training barrel downwards to the extent of the design of said cam surface. Preferably, the forward edge of the ejection port may be chosen to bear against the barrel""s camming surface, but another portion of the slide may effect this function.
The forward vertical face of the ejection port, however, tends to wear after only a relatively few impacts with the longitudinally immobile cam surface of the training barrel, thereby retarding downward movement of said training barrel and compromising reliable ejection. In addition, this worn surface would make the slide unusable when firing standard service ammunition, and hence would constitute a modification to the slide, which is not permitted.
To counter this deficiency, a deflection plate may be inserted over the vertical face at the forward end of the ejection port. This deflection plate, which is of sufficient strength to resist repeated impacts from the cam surface of the training barrel without wear, is designed in conjunction with said cam surface to ensure that the most downward position of the training barrel is always in line with the ejector. Thus, a spent training case, upon exiting the chamber of the training barrel when said training barrel is at its most downward position, will strike the ejector and be thrown through ejection port in the slide in a positive, reliable and normal manner.
More particularly, the invention is directed to an automatic pistol having:
(a) a frame;
(b) a slide mounted on the frame, said slide having an ejection port formed therein; and
(c) a training barrel with chamber and muzzle ends carried by the frame and having an upper surface that carries a camming face that is aligned with a portion of the slide
wherein the slide, in effecting rearward sliding displacement with respect to the frame during firing, passes over and bears against the camming face on the barrel, deflecting the chamber end of the barrel downwardly.
The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow.